macOS features hidden devices. These are devices that will
not be shown in the macOS UIs and that cannot be retrieved
without having the specific UID of the hidden device. There
are cases when you might want to have a hidden device, for example
when having a virtual speaker that forwards the data to a virtual
hidden input device from which you can then grab the audio.
The blackhole project supports these hidden devices and
this patch provides a way that if the device id is a hidden
device it will use it instead of check the hardware list of devices
to understand if the device is valid.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2251>
